Feb 3, 2010 (CIDRAP News) – The US Centers for Disease Control and Prevention (CDC) yesterday notified healthcare providers that 50 lots of Sanofi Pasteur's pandemic H1N1 vaccine in prefilled syringes have a shorter shelf life than shown on the label.

The CDC said in its Health Alert Network message that Sanofi's routine stability testing of vaccine that had already been shipped to providers showed that although the lots remained potent, they are losing potency more rapidly than expected. The company said the prefilled syringe doses in the affected lots should be used by Feb 15, 2010, regardless of the expiration date shown on the package. The new expiration date does not apply to multidose vials.

The 50 lots subject to yesterday's expiration change comprise 12 million doses. Fourteen of the lots are single-dose pediatric flu vaccine, and the remaining 36 are single-dose vaccine for older children and adults. The lots were shipped to providers between November 2009 and January.

The CDC said there are no safety concerns with the affected lots and that people who were immunized with doses from the lots do not need to be revaccinated.

The CDC said its notice yesterday applies specifically to the 50 lots of vaccine but that the expiration date change and two earlier non–safety-related recalls apply to all of Sanofi's pandemic prefilled syringe vaccine doses.

The CDC emphasized that though most of the doses have already been administered, it was almost certain that some haven't yet been used.

In an earlier Health Alert Network notification detailing a Jan 29 non–safety-related recall of five lots of Sanofi pandemic vaccine totaling 1.3 million doses, the CDC said Sanofi planned to submit a field correction request to the Food and Drug Administration (FDA) to change the expiration date of its remaining pediatric and adult prefilled syringes.

A spokesman for the CDC told CIDRAP News that Sanofi submitted the field correction request and that the FDA approved it.

In addition to the Jan 29 Sanofi vaccine recall, there have been two others, both in December, related to a drop in potency after shipping. One involved Sanofi pediatric prefilled syringe doses and the other was from MedImmune, the company that makes the nasal spray H1N1 vaccine.